• Fisheries and Aquatic Sciences
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• v.4 no.4
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• pp.261-264
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• 2001

Seasonal variation in fatty acid profiles was examined in the visceral mass and the posterior adductor muscle of the female pen shell, Atrina pectinata. Total percentages of saturated fatty acids were similar between the two organs, and there was not a prominent seasonal change in both tissues. While the percentages of highly unsaturated fatty acids (HUFAs) in the visceral mass were higher than those in the posterior adductor muscle, monounsaturated fatty acids (MUFAs) were high in the posterior adductor muscle. HUFA contents, especially in $20: 5\omega3$, $22: 5\omega3$ and $22: 6\omega3$, markedly decreased in September in the visceral mass, and this decrease was associated with a corresponding total MUFAs in the same organ. A similar pattern of change in September was noted in the posterior adductor muscle MUFAs and HUFAs. These results indicate that $20:\omega3$ and $22:\omega3$ HUFA changes in the visceral mass and posterior adductor muscle reflect the reproductive stages in pen shell.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.6
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• pp.1877-1891
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• 2022

As a part of cloud computing technology, algorithms for cloud task scheduling place an important influence on the area of cloud computing in data centers. In our earlier work, we proposed DeepEnergyJS, which was designed based on the original version of the policy gradient and reinforcement learning algorithm. We verified its effectiveness through simulation experiments. In this study, we used the Proximal Policy Optimization (PPO) algorithm to update DeepEnergyJS to DeepEnergyJSV2.0. First, we verify the convergence of the PPO algorithm on the dataset of Alibaba Cluster Data V2018. Then we contrast it with reinforcement learning algorithm in terms of convergence rate, converged value, and stability. The results indicate that PPO performed better in training and test data sets compared with reinforcement learning algorithm, as well as other general heuristic algorithms, such as First Fit, Random, and Tetris. DeepEnergyJSV2.0 achieves better energy efficiency than DeepEnergyJS by about 7.814%.

• Development and Reproduction
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• v.19 no.3
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• pp.153-161
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• 2015

For the 2 years of farming, at the indoor circulating aquaculture system, four kinds of skeletal deformities were found among 60 Far Eastern catfish, Silurus asotus. Deformities saw jawbone's luxation, abnormality of upper lip and malocclusion. Spinal deformity was most fatal deformities with low weight and small length. Jawbone's luxation had 1 maxilla and 2 mandibles. Abnormality of upper lip had just lip was back over. Malocclusion's left maxilla and right maxilla were not balanced. This experiment was any deformities in this species through the deformity can grasp how it affects.

• Ocean and Polar Research
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• v.44 no.4
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• pp.339-353
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• 2022

The purpose of this research is to conduct an empirical analysis regarding Korea's 'Marine Protected Areas (MPA)' from an international comparative perspective. The authors would like to present the policy direction of marine protected areas based on the result of the research. The result of this study can be summarized in the following manner: First, the total designated size of marine protected areas in Korea is very small compared to the sizes of other OECD nations . Second, while some nations have expanded the extent of marine protected areas in accordance with international agreements and criteria, Korea has not done so. Accordingly, we propose the designated dimensions of marine protected areas should be constantly expanded to keep pace with international trends.

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.226-229
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• 2007

Survival, tag retention and tag readability were compared among the control and three treatment groups of soft-shelled turtles, Pelodiscus sinensis Crother, 2000 (mean body $weight{\pm}SD$: $182.6{\pm}13.7\;g$), marked with visible implant fluorescent elastomer (VIFE) tags for 16 months. Mortality 4 to 16 months after tagging was attributed to collection and handling stress rather than to the tagging itself. Tags applied to the web surface between the fourth and fifth dactyl of the hindfoot appeared to have the highest retention rates, while adipose eyelid tagging had high tag readability but a high loss rate. We conclude that in soft-shelled turtles, the most suitable region for VIFE tagging is on the web surface between the fourth and fifth dactyls of the hindfoot.

• Ocean and Polar Research
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• v.45 no.2
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• pp.71-87
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• 2023

Climate change causes ocean warming, ocean acidification, sea-level rise, dynamic coastal risk, change of ecosystem structure and function, and degradation of ecosystem services. Not only that, but it has negatively impacted the well-being of people, society, and culture, including food security, water resources, water quality, livelihood, health, welfare, infrastructure, transport, tourism, recreation, and so on, especially by particularly degrading indigenous communities and generating an inequitable distribution of benefits and costs. As pointed out here, these adverse impacts of climate change on the ocean have been emphasized at the international and national levels. In contrast, the ocean field has been neglected in the climate change conversation for too long. However, since the UNFCCC COP 25, the ocean has been drawn into the discussion as a solution to address climate change. Moreover, the U.S. Congress recently unveiled a bill called the 'Ocean-Based Climate Solution Act, OBCSA' that reflects the new paradigm of the international regime. The comprehensive legislative bill includes elements related to climate inequity, a blue economy, and a community-led bottom-up policy mechanism, which will have a significant bearing on the ocean-climate legal system. Therefore, this study reviews the OBCSA and deduces implications with regard to the ocean-climate legal system in Korea.

• Fisheries and Aquatic Sciences
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• v.20 no.9
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• pp.21.1-21.10
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• 2017

The aim of this study was to assess visible implant fluorescent elastomer (VIE) tagging and stress response in marine medaka, Oryzias dancena. The experimental fish were anesthetized individually and marked with red, yellow, or green elastomer at each of the following three body locations: (1) the abdomen, (2) the back, and (3) the caudal vasculature. During 12 months, the accumulated survival rates of fish in the experimental treatments were not different among red, yellow, and green elastomers. The experimental fish retained > 85% of the tags injected in the back, > 70% of the tags injected in the caudal vasculature, and > 60% of the tags injected in the abdomen (P < 0.05). An important observation was that the abdomen site was associated with poor tag retention. For all injected sites, the red and green tags were able to be detected more easily than the yellow tags when observed under both visible and UV lights. Tag readability was lower for the abdomen site than for the other sites (back and caudal vasculature). Thus, VIE tags were easy to apply to marine medaka (< 1 min per fish) and were readily visible when viewed under UV light.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.352-361
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• 2021

An underwater positioning method that can be applied to structures for underwater construction is being developed at the Korea Institute of Ocean Science and Technology. The method uses an extended Kalman filter (EKF) based on an inertial navigation system for precise and continuous position estimation. The observation matrix was configured to be variable in order to apply asynchronous measured sensor data in the correction step of the EKF. A Doppler velocity logger (DVL) can acquire signals only when attached to the bottom of an underwater structure, and it is difficult to install and recover. Therefore, a complex sensor device for underwater structure attachment was developed without a DVL in consideration of an underwater construction environment, installation location, system operation convenience, etc.. Its performance was verified through a water tank test. The results are the measured underwater position using an ultra-short baseline, the estimated position using only a position vector, and the estimated position using position/velocity vectors. The results were compared and evaluated using the circular error probability (CEP). As a result, the CEP of the USBL alone was 0.02 m, the CEP of the position estimation with only the position vector corrected was 3.76 m, and the CEP of the position estimation with the position and velocity vectors corrected was 0.06 m. Through this research, it was confirmed that stable underwater positioning can be carried out using asynchronous sensors without a DVL.

• Journal of fish pathology
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• v.35 no.2
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• pp.195-203
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• 2022

This study was performed to delineate pharmacokinetic residue characteristics of lincomycin (LM) in olive flounder at low water temperature (13℃), and to examine whether LM is effective against main Gram-negative pathogens. It was observed that the times for residue declined below the maximal residue limit (0.1 mg/kg) in the muscle was, respectively, 32, 33 and 55 days following 10, 20 and 40 mg/kg intramuscular LM injections. The in vitro MIC value of LM against Edwardsiella piscida was higher than 256 ㎍/mL and against Vibrio harveyi 32 ㎍/mL when examined with several clinical isolates. These results suggest that the withdrawal time of LM should be more than 30 days in consideration of the 10 mg/kg employed as the regular clinical dose. It was also found that LM administered to treat streptococosis in olive flounder is not likely to be effective against some pathogenic Gram-negative bacteria.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.158-159
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• 2023

With the development and state-of-the-art of ocean satellites, wide-area management of the waters around Korea has become possible. In particular, in the field of ship operation, as autonomous navigation technology based on artificial intelligence and big data is being developed, there is a need for additional analysis and observation through ocean satellite data.. Researches that can combine ship operation with ocean satellite data include ship detection based on ocean satellites and ship navigation assistance using marine weather forecasting.